Yup, I'm just getting started in the Maritime industry in the US, but here is what I know:
Hopefully, you're on the East coast. This is where the majority of Maritime Academies are located. There are 2 in the NYC area (SUNY Maritime, US Merchant Marine Academy (federal school)), 1 in MAssachusetts on Cape Cod area (Mass Maritime), another way up the coast in Castine, Maine (Maine Maritime).
I don't know much about USMMA, other than they are across the river from SUNY Maritime. The other schools are all basically 4 year public schools, and you graduate with your 3rd mate/engineer license upon graduation assuming you want the license. Each of these institutions have a training ship that will go out on Sea Terms either in summer or winter, giving you the sea time you need for the license.